Philips 40PFL5505d/f7 Plays 21

[rdagijones]

Working on a friend's Philips TV 40PFL5505d/f7. If the TV is off for a while it works fine for about 10 minutes. After that, no video and no sound and the power light blinks 21 times then a break and continues this cycle until unplugged. From Internet search suggestions, I have replaced the Inverter board (SSI400_12D01 Rev 0.3) and the Power supply board (UPBPSPDEL002) and still no joy. I really should have started here. Any suggestions?

[thoma]

Re: Philips 40PFL5505d/f7 Plays 21

What Chassis do you have
look at the sticker on the backside of the lcd tv
regards thoma

[rdagijones]

Re: Philips 40PFL5505d/f7 Plays 21

I don't see anything labeled as chassis but here is the sticker.

[budm]

Re: Philips 40PFL5505d/f7 Plays 21

P & F USA Inc. This is FUNAI rebadged as PHILIPS, not the real old Philips sothey do not put the chassis number on the sticker like the old Philips.
http://www.funai.jp/en/company/network.html

Are these the boards used in your TV?
http://www.shopjimmy.com/catalogsear...ips+40PFL5505d

[Sevenqi]

Re: Philips 40PFL5505d/f7 Plays 21

Please check the regular IC on the main board near the t-con cable, this IC probable not working, then the t-con has no 12V voltage.

[thoma]

Re: Philips 40PFL5505d/f7 Plays 21

It is a PL10.4 Chassis look in the right corner of the sticker in the photo
there it stands!Original from Funai!
regards thoma

[budm]

Re: Philips 40PFL5505d/f7 Plays 21

It is a PL10.4 Chassis look in the right corner of the sticker in the photo
there it stands!Original from Funai!
regards thoma

Ah , you are correct.
Service manual:

[neilc6]

Re: Philips 40PFL5505d/f7 Plays 21

Just got this model TV with the same problem. Front LED does a 21 blink code. Service manual is available online. Following the troubleshooting flowchart, I get 5V at CN3002 pin 6 (AL+5V) and 3V on pin 3 (P_ON_H1) which is a power on control signal from the main board. Flowchart indicate PS board is at fault. The block diagram shows this signal going through some transistor switches to an optoisolator enabling LCD voltages. Optoisolator input is measuring 1.2V which is the forward voltage with one leg ground.

Please check the regular IC on the main board near the t-con cable, this IC probable not working, then the t-con has no 12V voltage.

Saw this comment but wasn't to sure. Checked TCON voltage and there was no voltage. The regulator IC on the main board is marked Q4902. Schematic indicates part is TPC8123.

[neilc6]

Re: Philips 40PFL5505d/f7 Plays 21

Going over the schematic and datasheet, this part is not a regulator but a P-Channel MOSFET used to switch the LCD+12V going to the TCON. Closest substitue I could find on Digikey is DMP3020LSSDICT-ND

[dskall]

Re: Philips 40PFL5505d/f7 Plays 21

Are you getting all your power supply voltages? Are you getting 12v at fet?

[neilc6]

Re: Philips 40PFL5505d/f7 Plays 21

Yes - checked the voltages at the FET and getting 12V and gate voltage and nothing out. Bit difficult since the main board is mounted on a shield but at least the IC is on the top side. Taped the board down with an insulator behind it to be able to measure with it plugged in.

[neilc6]

Re: Philips 40PFL5505d/f7 Plays 21

Replaced the FET but same result. Put the old FET into my ESR tester and it was ok. Pretty sure I measured about 4V on the gate pin before but now getting the same as the 12V at the source so it's not turning on. Checked all supply voltages and they are ok. Checked all main board regulators and they are ok. I have no LCD-P-ON and also no LCD-ON (which maps to Backlight-SW on the connector) from the main processor.

Considered shorting or putting a manual switch for LCD-P-ON (which would power up the TCON) but don't think this would help since I still need a Backlight-SW signal which goes to the inverter boards.

Another option is to put a heat gun to the main processor in case of bad BGA connections.

Opinions?

[dick_barton]

Re: Philips 40PFL5505d/f7 Plays 21

Have you checked Q4901?

[aaronwt6]

Re: Philips 40PFL5505d/f7 Plays 21

Replaced the FET but same result. Put the old FET into my ESR tester and it was ok. Pretty sure I measured about 4V on the gate pin before but now getting the same as the 12V at the source so it's not turning on. Checked all supply voltages and they are ok. Checked all main board regulators and they are ok. I have no LCD-P-ON and also no LCD-ON (which maps to Backlight-SW on the connector) from the main processor.

Considered shorting or putting a manual switch for LCD-P-ON (which would power up the TCON) but don't think this would help since I still need a Backlight-SW signal which goes to the inverter boards.

Another option is to put a heat gun to the main processor in case of bad BGA connections.

Opinions?

I had a friend's 55" version of this TV doing the same thing. I connected the LCD-ON and Backlight ON connectors directly to the PS-ON on the power supply since I had no signals for those from the main board. The main was too expensive to replace. He's been watching it like this for over 2 years now. Only thing is it now displays a blank, backlit screen for about 10 seconds before the splash screen comes up. Of course, this is expected since the backlight comes on instantly.

[dskall]

Re: Philips 40PFL5505d/f7 Plays 21

Looks like a few caps and resistors you can check

[dick_barton]

Re: Philips 40PFL5505d/f7 Plays 21

I had a friend's 55" version of this TV doing the same thing. I connected the LCD-ON and Backlight ON connectors directly to the PS-ON on the power supply since I had no signals for those from the main board. The main was too expensive to replace. He's been watching it like this for over 2 years now. Only thing is it now displays a blank, backlit screen for about 10 seconds before the splash screen comes up. Of course, this is expected since the backlight comes on instantly.

Q4902 has been changed but it is driven by Q4901 from the LCD_P_ON signal so I would still check that transistor.

[neilc6]

Re: Philips 40PFL5505d/f7 Plays 21

I probed the base of Q4901 which is LCD_P_ON and it never goes high. Sounds like I should connect both LCD_ON and LCD_P_ON to P_ON_H1 (3.1V)

[neilc6]

Re: Philips 40PFL5505d/f7 Plays 21

I connected P_ON_H1 to the 100 ohm res before pin 1 on the main board connector (going to Backlight-SW) and to the 430K resistor driving the the input to the base of Q4901. The TV turned on and promptly shutdown and I guessed that the P_ON_H1 line was being overdriven since it was still feeding into the two outputs directly. I rewired so the old outputs were open circuited.

TV now splashes on with some lines right away which go away, backlight stays on but still get the 21 blinks. I'm thinking there is something wrong with the processor since it is not starting up although I get the P_ON_H1 signal.

Will try the heat gun on the processor before scrapping the TV since a used main board is way too expensive.